Method for simulating bombing



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Patented Feb. 9, 1943 anatra METHOD FOR SIMULATING BOMBING Ambrosius Briechle, Brooklyn, and Roy T. Hurley, Dobbs Ferry, N. Y., and George E. Merritt, Lusby, Md., assignors to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Original application March 22, 1938, Serial No. 197,402, now Patent No. 2,283,788, dated May 19, 1942. Divided and this application October 21,1939, Serial No. 300,572

4 Claims.

This invention relates to a method for simulating aircraft bombing.

This application is a division of the copending application Serial No. 197,402, led March 22, 1938, for Bombing camera now Patent 2,283,788, May 19, 1942.

An object of this invention is to provide a novel method for determining the theoretical point of impact of an actual or imaginary bomb released from an aircraft.

' A further object is to provide a novel method for training personnel in bombing technique.

Another object is to utilize photographic means to provide a novel method for simulating aircraft bombing whereby permanent records for checking the accuracy of the bombing results are secured.

A still further object is to provide a novel method for training personnel in bombing wherein all the operations in actual bombing, except the release of a bomb, take place.

The above and further objects and novel features of the invention will more fully appear from the following description when the same is taken in connection with the accompanying drawings. It is to be expressly understood, however, that the drawings are for the purpose of illustration only and are not intended to dene the limits of the invention, reference being primarily had for this latter purpose to the appended claims.

In the drawings, wherein like reference characters refer to like parts throughout the several views,

Fig. 1 is a front elevation, with parts broken away and partly in section, of one embodiment` of the present invention, showing a cone, a magazine and a cover in normal operative positions;

Fig. 2 is a sectional view of a part of the lm rolldrive taken substantially on line 2-2 of Fig. l;

Fig. 3 is a detail top plan view of the magazine with the cover removed;

Fig. 4 is a rear elevation of the magazine with the cone and cover removed and with parts broken -away to show the details of the counter structure;

Fig. 5 is a sectional view taken substantially on line 5 5 of Fig. 3 with the cone and cover in operating position and showing the uid conduit connection from the cone to the magazine;

Fig. 6 is a sectional view taken substantially on line 6-6 j of Fig. 3 with the cone and cover*` in operating position;

Fig. 7 is a similar view taken en line 1-1 of Fig. 6' Y Fig.8 is a sectional View taken substantially on line 8-8 of Fig. 3 and showing a means for locking the pressure plate against accidental or inadvertent movement after removal of the c-one;

Fig. 9 is a sectional view taken substantially on line 9-9 of Fig. 7;

Fig. 10 is a top plan view, with parts broken away and partly in section, the section being taken substantially on line IO-I of Fig. 1;

Fig. 10a is an enlarged sectional View taken substantially along line llico-10a of Fig. 10;

Fig. 11 is a detail sectional view, with parts broken away, taken substantially on line Il--ll of Fig. 10;

Fig. 12 is a sectional view taken substantially on line l2-I2 of Fig. 10;

Fig. 13 is a similar view taken on line l3|3 of Fig. 10;

Fig. 14 is a sectional view, with parts broken away, taken substantially on line lli-I4 of Fig. 1, showing, partly in plan and partly in section, the shutter mechanism andthe control and drive therefor;

Fig. 15 is a somewhat enlarged rear elevation, partly in section, showing a form of spring drive utilized for motivating the shutter rolls;

Fig. 16 is a similar view taken substantially on line lli- I6 of Fig. 14;

Fig. 17 .is a somewhat enlarged sectional View, taken substantially on line l'l-l'l of Fig. 14, showing a form of cam means adaptable for releasing the shutter curtain;

Fig. 18 is a similar view taken substantially on line |8--i8 of Fig. 14;

Fig. 19 is a sectional view taken substantially on line I9-I9 of Fig. 14 showing the relative positions of the shutter mechanism and the lenses; Y

Fig. 20 is a lateral, substantially central, sectional View of the completely assembled camera showing the lens structure partly in elevation and partly in section;

Fig. 21 is a sectional View taken substantially along line 2l-2I of Fig. 22 showing one form of electrical motor adapted for driving the various camera mechanisms;

Fig. 22 is an end sectional View taken subbled camera showing an interval meter and the.

motor mounted in operative position;

Fig. 24 is a section through the interval meter taken substantially along line 24--24 of Fig. 23, and showing the operating parts thereof in top plan view;

Fig. 25 is a sectional view taken substantially along line 25-25 of Fig. 24;

Fig. 26 is a front elevation of the interval meter with parts broken away;

axes by merely inserting the rolls into the magazine chamber in the general direction of the final position which said rolls will assume. The novel means consist of a three-point support for each of the film roll end pieces, two of said supports in each instance serving to determine the film Fig. 27 is a sectional view taken substantially along line 21-21 of Fig. 26;

Fig. 28 is a sectional view taken substantially along line 28-28 of Fig. 27 and showing the motor for driving the interval meter;

Fig. 29 is a longitudinal sectional view through the camera with parts broken away showing the auxiliary optical system for photographically recording bombing data;

Fig. 30 is a section taken substantially along line Silof Fig. 29 showing the details of the optical system and the film maintaining and metering means;

Fig. 31 is a sectional View taken substantially` along line 3|-3|v of Fig. 29 showing the various instruments for giving the data to be recorded;

Fig. 32 is a sectional view with parts broken away taken substantially along line 32-32 of Fig. 31 and showing in detail the manner in which one of the instruments is mounted; and,

Fig. 33 is a diagram of one form of electric circuit suitable for energizing the drive and control mechanisms.

In the illustrated embodiment, the camera of the present invention is shown as having two major sections, i. e., a magazine 23 in which the lm is housed, suitably positioned, and metered for exposure, and a cone 24 in which the driving and control mechanisms, the shutter and the lenses are mounted. A cover 25 is provided for the magazine serving to keep said magazine dust and light-proof and to cooperate with parts of the magazine and perform other useful functions, to appear later. It will be noted that the section housing the film and the section housing the lenses are, by the present construction, adjacent each other permitting means, hereinafter more fully described, to be utilized which may fix the film plane independently of the accuracy with which the cone is mounted on said magazine.

Magazine and cover Magazine 23 comprises a main casting 26 having two longitudinally spaced, upwardly extending walls 21. and 28 (Figs. 1, 3 and 6), which walls, in combination with cover 25, form a central chamber 29, in said magazine. Two film rolls 3i) and 3| (Fig. '1) are adapted for rotation about fixed longitudinal axes in said chamber, and the unexposed film, preferably wound upon roll 30, is adapted to be unwound therefrom and exposed by means to be hereinafter more fully described, and then rewound upon roll 3|. Rolls 30 and 3| are alike and of the standard type construction well-known to the art, having two end pieces of circular shape in the form of discs and a central cylinder of a lesser diameter than said end pieces upon which the film is.wound.

Heretofore, film rolls for aerial cameras have been fixed for rotation in the magazines of said cameras by trunnions located at the centers of rotation. However, in the present device, in order to facilitate camera loading, this method of central support has been eliminated and novel means are provided whereby the film rolls are positioned for rtation'about fixed longitudinal 'two shafts 32 and 33 which are journalled for rotation in walls 21 and 28 and which extend longitudinally therebetween. Mounted on the ends of the shaft 32 adjacent the internal faces of the walls 21 and 28, respectively, are supporting rolls 34 and 35 on which the end pieces of film roll 3|) are adapted to rotate. Similarly mounted for the same purpose on shaft 33 are rolls 36 and 31 and a similar construction comprising shafts 33 and 39 and supporting rolls 40, 4|, 42 and 43 is provided for mounting lm roll 3 I Placing the end pieces of each film roll on the supports hereinbefore described determines the longitudinal axes of rotation for the film rolls. However, to x the film roll end pieces so that they will remain in contact, and rotate with the supporting rolls, a third support adapted to be resiliently' held against the end piece is provided. Rolls 44 and 45 (Figs. 3 and 7), secured to a shaft 4G for rotation therewith, function to hold film roll 30 as the third supports therefor, and are resiliently urged by means of a pair of arms 41 and 48 into engagement with the end pieces of said lm roll. Arms 41 and 48 support shaft 46 and are pivotally mounted on a second shaft 43 which, in turn, is journalled in suitable bearings in an upper central portion 50 of the magazine casting. Portion 5D may be cast ntegrally with the main casting of the magazine or may be suitably affixed to said casting between walls 21 and 28. In order to resiliently urge rolls 44 and 45 into engagement with the end pieces, a pair of light coil springs 5| and 52 are wound about shaft 49. Each of said springs has one end thereof bearing upon one of the arms 41 or 48 and the other end thereof bearing upon portion 50 and each tends to expand and urge the arm with which it cooperates into engagement with film roll 3U. The force exerted upon said roll due to said springs is only sucient to prevent said roll from falling out of said magazine when the same is inverted with cover 25 removed, as for example, when the lm is being threaded into position. A structure which is the duplicate of the above-described means for holding roll 30 in operative position is also provided for holding roll 3| and comprises coil springs 53 and 54, arms 55 and 56 pivotal about a shaft 51 and rolls 58 and 5S mounted upon a shaft 6U. Other resilient means, in the form of a leaf spring 60a, are also provided in cover 25 being suitably secured thereto to have the spring ends bear against the central portions of shafts 46 and 60 and thereby yieldingly urge the supporting rolls mounted on said shafts into engagement with the film rolls.

After inserting film rolls 30 and 3| into the magazine by merely raising shafts 60 and 46 (the cover being removed), and dropping said film rolls in position, the loading of the camera is effected by threading the film 6| (shown by a broken line in Fig. 7), from roll 30, over an idler roll 62, xed to shaft 32 (Fig. 9), then under a pressure plate 63, and thence over a metering drum 64 to lm roll 3|, said metering drum being secured to and rotatable with shaft 39. The fllm is fixed to roll 3| by any suitable method as, for example, by insertion of the end of the film into a slot arranged therefor in the cylinder of said roll.

After the film has been loaded into the magazine in the manner above described, cover 25 is placed thereon. AThe walls 21 and 28 (Fig 6) have flanges 65 and 66, respectively, 'extending the length of the upper edges thereof and said flangesare adapted to flt into grooves 61 and 68, respectively, provided therefor in cover' 25 and to thereby form a light trap keeping light from entering chamber 29. Similar light traps between the lower edge of said cover and magazine casting 26, comprising flanges 69 and 10 (Fig. 7) in said magazine and grooves 1| and 12 in said cover, complete the means whereby chamber 29 is kept light-proof. To keep the magazine interior dust-proof, an additional groove 'Ha is provided in main casting 26 along the edge thereof completely circumscribing the magazine interior and having a strip or Washer 12a of some yielding substance such as rubber or felt fixed therein. l The bottom of the cover when the latter is correctly positioned on the'magazine ts over said strip and compresses the same, thereby producing a dust-proof joint or connection between said magazine and cone.

Novel means are provided for locking cover 25 to magazine 23 by merely placing said cover over said magazine and then exerting a slight down- Ward pressure thereon. After the cover has been thus fixed in position,` release of said locking means can only be effected by rotation vof a thumb screw 13 (Figs. 1 and 3) thus insuring against accidental or inadvertent removal of the cover during operation of the camera. As shown, said locking means comprises a shaft 14 mounted for rotation in bearings 15 and 1S located in walls 21 and 28, respectively, and in upwardly extending lugs 11 and 18 (Figs. 6 and 7) cast integrally with or rigidly fixed to portion 58 of the magazine casting. Shaft 14 has a part thereof projecting outside of wall 28 and has thumb' screw 13 mounted on this projecting portion. A slot or opening 19 is provided in cover 25 in order that thumb screw 13 may extend throughsaid slot and be operable from the. exterior of said cover.

A pair of Worms 89 and 8|, preferably integral with shaft 14, are rotated thereby and are adapted to engage and rotate worm gears 82 and 83, respectively (Fig. 3). Gear 82 is suitably secured to or integral with a vertical shaft 84 and the lower end of the latter extends through portion 58 and is held against axial movement by means of a collar 85 afxed thereto. A portion 86 of said shaft also extends upwardly above gear 82 and is suitably threaded so that a split nut 81 secured to cover 25 may engage the same. Said nut is split into two segments, each of which is pivotally mounted in a casing 88 fixed to cover and a coil spring 89 is wound about said segments to keep the same together and normally operative as a single nut. However, threaded portion 86 of shaft 84 may be made to engage the split nut without being screwed into said nut by having the latter forced down upon it, thereby prying apart the segments of said nut against the constricting force of coil spring 89 and permitting said threaded portion to be grasped by said nut. Thumb screw 13 may be rotated thereafter to further increase the threaded engagement between nut 81 and porboss.

tion 86, threadingv the latter into the former through the VWorm vand gearl 80, '82'. A split nut means similar to that described above is provided for cooperating with worm and gear 8|, 83, so that rotation of shaft 14 by thumb screw 13 also controls the locking and releasing of said unit. Both units are unlocked for removal of the cover by rotation of shaft 14, said shaft operating the worm and gear drives of the threaded shafts and causing rotation of said threaded shafts in a direction to unscrew the same from the split nuts.

In order to expose a new frame of film after each photograph is taken, metering drum 64 is rotated through a predetermined angular distance after each exposure and novel means are provided for maintaining the film in contact with said drum during rotation thereof so that the film may be' accurately metered thereby. The novel means comprise a pressure roll 98 (Fig. '7) suitably mounted on a shaft 9i which is journalled at each end in a bracket 92, pivotally mounted by means of a pin 93 on the inner wall of cover A25. Resilient means, such Vas a leaf spring 94 are secured to said bracket, and when the cover is locked to the magazine, said resilient means urge pressure roll against metering drum 64 pressing the lm into frictional engagement with said drum. By mounting the pressure roll on the cover, the necessity for threading the lm between rolls during loading is eliminated and the process of loading is accomplished more readily and more quickly'than heretofore in cameras which had the pressure roll and the metering roll mounted in the magazine in fixed relation to each other.

Movement of the lm by means of metering drum 64 rotates idler roll B2and unvvinds the lm from lm roll 39, causing the latter to rotate in aclockwise direction as viewed in Fig. '7. In order to frictionally resist the free rotation of said film roll and keep the lm under a slight tension so as to minimize the possibility of wrinkling, means; such as a friction disc'95 (Fig. 9) are provided in the magazine for applying a frictional force which tends to retard the rotation of film roll 38. A hollow boss 9B is cast integrally with wall 21 of the magazine and friction disc 95 is mounted on a rod 91 which extends through said boss and has a collar S8 secured to the outer end thereof. Disc 95 is held in frictional engagement with the end piece of roll 30 by the expansive force of coil spring 99 interposed between said disc and the bottom of said boss and surrounding rod 91 within said A pin l0!) mounted in wall 21 and extending into an opening lill in disc 95 holds said disc against rotary movement. A similar disc (not shown) is preferably provided in wall 28 directly opposite disc 95 for the other end piece of film roll 38. As a result, a pull must be exerted upon the lm which is sufficient to overcome the resistance of the friction discs. The latter, in addition to keeping the film taut, serve to center the film roll between the walls 21 and 28, this being one reason why a pair of 3) on which the end pieces of said lm roll rest.

The end pieces are adapted 'to slip on said supporting rolls while being driven thereby because the speed at whichsaid supportingA rolls tend toV drive the fllm is in excess of Vthe speed at which said film roll must rotate to take up all the film passing from the metering drum. As a. result, the film is kept taut between said drum and said lm roll while being wound upon the latter.

Means located in the cone, to be hereinafter more fully described, are provided for driving the mechanism which imparts rotatry motion to the metering drum 64 for moving the film and to the two supporting rolls 40 and 4| for driving lm roll 3|. Said mechanism comprises an upper member of a jaw coupling |2 (Figs. l and 8) integral with or suitably fixed to a hollow shaft |83, said shaft being journalled for rotation in a set of ball bearings |04. A bevel gear secured to the upper end of shaft |03 meshes with a bevel gear |06 aixed to a shaft |01 and is adapted to drive the latter which is journalled for rotation in suitable bearings mounted in a pair of downwardly extending arms |08, I9 of a bracket ||0. The latter is secured by screws to the outside face of wall 21 of the magazine casting.

To actuate supporting rolls 40 and 4|, a shaft ||2 is drivably connected to shaft |01 by means of a pair of engaging helical gears ||3 and 4, the former being fixed to shaft I1 and the latter to the end of shaft |`|2. The latter extends through and is journalled for rotation in walls 21 and 28 and has secured thereto a pair of spur gears ||5 and ||6 (Fig. 3), gear ||5 (Fig. 2) being mounted adjacent the outside face of wall 21 and meshing with spur gear H1. The latter is keyed to the hub of supporting roll 40, which bears on but rotates freely of shaft 39, and drives said roll. Spur gear I6 (Fig. 3) is similarly mounted adjacent the outside face of wall 28 and meshes with gear ||8, to drive supporting roll 4| at the same speed and in the same manner as roll 40 is driven. Accordingly, film roll 3| is driven at both ends by supporting rolls 40 and 4| and applies a uniform force across the width of the lm during the winding thereof.

Metering drum 64 is rotated by a worm ||9 (Figs. 1 and 8) fixed to shaft |01 and a Worm wheel |20 fixed to shaft 39, the latter shaft having said drum secured thereto for rotation therewith. The worm drive rotates drum 64 at a slower speed than the helical drive through which supporting rolls 40 and 4| are driven, producing the tension in the portion of film between said metering roll and the film roll.

In order to provide exact and clear photographs, a high degree of accuracy in xing the film plane, so that it coincides with the focal plane, is necessary. Novel means, mounted in the magazine and adapted to cooperate with cone 24, are provided for locating the film plane, said means comprising pressure plate 63 (Fig. '7) and an accurately finished, plane surface |2| which fixes the position of the film and the pressure plate plane with relation to the lenses. Surface |2| which is part of the cone casting is accurately finished in a plane and the lenses are subsequently adjusted to have the focal planeV thereof coincide with said plane. Pressure plate 63 is preferably a metal casting, substantially rectangular in shape, having its lower face finished and grooved and being of suicient size to cover an opening |22 in the upper end of the cone casting. The film is urged into contact with the base of said pressure plate by means to be described hereafter, and the sensitive side of said film is exposed in the direction of opening |22' so that a photographic impression may be made thereon when the shutter is released. Surface |2| is the top surface of a flange |23 integral with the upper end of the cone casting, said flange defining opening |22.

Normally, pressure plate 63 is yieldingly urged into contact with nished surface |2| of the cone casting by means comprising a pair of vertical arms or rods |24 and |25 (Fig. 6), mounted in recesses provided therefor in said pressure plate and held in said recesses by pins |26 and |21, respectively. A pair of inwardly extending lugs |28 and |29 cast integrally with wall 21 are provided, having openings suitably bored therein in which rod 24 is slidably mounted and which guide said rod in any vertical movement thereof. A collar |30 is fixed to rod |24 between lugs |28 and |29 and a compressed coil spring 3| is mounted between said collar and upper lug |28, surrounding said rod and exerting an expansive force upon collar |30 which tends to move plate 63 in a downward direction into contact with cone surface |2|. A similar structure to that above described, comprising lugs |32 and |33, coil spring |34 and collar |35, is provided in combination with rod |25 and exerts a downward force, augmenting the force of spring |3| upon the pressure plate. Rods |24 and |25 are loosely mounted in the openings provided therefor in the guiding lugs, an appreciable clearance existing between said openings and said rods in order that the base plane of the pressure plate may be aligned by the plane of finished surface |2| when brought in Contact therewith even though the magazine is slightly askew in relation to the cone. As a result, pressure plate 63 is normally yieldingly held in the plane of finished surface |2|, i, e., the focal plane of the camera lenses, and positions the film accordingly.

In order to expose a new frame of film after a photograph has been taken, the force normally exerted upon the film by pressure plate 63 must be overcome so that metering roll 64 may move the film. Accordingly, means are provided whereby pressure plate 63 is raised against the force of springs |3| and |34, relieving the pressure upon the film and permitting free movement thereof, said means, as shown, comprising a pair of arms or levers |36 and |31 which extend into slots |38 and |39, respectively. Slot |38 is adjacent to rod 24, being suitably positioned in the pressure plate casting to have pin |26 extend therethrough and to have said pin engaged by the pronged end of arm |36 (Fig. 7). Arm |31 similarly engages pin |21 and is, together with arm |38, secured to a shaft |40 for rotation therewith. Shaft |40 is journalled in walls 21 and 28 and has a portion thereof extending outside of wall 21, to which a lever 4| is affixed (Figs. 1, 3, 6, and 8). Lever |4| is adapted to rotate shaft |40 by transmitting thereto the reciprocal motion of a rod |42 (Fig. 8) so that whenever rod |42 is raised, lever |4| rotates in a counter-clockwise direction and like- Wise moves arms |36 and |31 thereby lifting pressure plate 63 sufficiently to clear the path of the film travel.

Rod |42 which reciprocates and actuates the above-described mechanism for raising pressure plate 63 is mounted concentrically with shaft |03 in the hollowed center thereof. The reciprocal movement is imparted to said rod by cam means, to be hereinafter more fully described, said means being suitably timed to move rod |42 in an upward direction raising pressure other.

l(Fig.

plate 63 once after each exposure and keeping said pressure plate in a raised position during the interval in which the exposed frame of film is displaced by an unexposed frame. When said unexposed lm frame has been suitably 'positioned between said pressure plate and surface |2| of the cone, the former is lowered into Aengagement with the latter and frictionally holds the film in the focal plane.

In order to eliminate any wrinkles or creases existent in the film after the saine has been moved by metering roll 64 into position under pressure plate 63, novel means are provided whereby the film is urged by uid pressure, against the base plane of said pressure plate, and is thereby smoothed out before being lowered into the xed plane of cone surface |2|. As a further precaution against wrinkling and creasing, and also to definitely fix the film in the focal plane, the same novel means are used a second time and urge the film into contact with the pressure plate when the shutter mechanism releases the shutter curtain to expose the film.

The novel fluid pressure means comprise a series of longitudinal and lateral channels or grooves |43 machined or cast in the base `plane of pressure plate 63 in such a manner that when a plane surface of any nature is brought into contact with the base plane of said pressure plate, said grooves constitute a group of fluid conduits each of which is connected to every An annular ange |44 (Figs. 6 and 7) preferably located at the center of pressure plate 63, is cast integrally with the upper surface of lsaid pressure plate and has a cap or cover plate |45 vsecured thereto by means such as screws |46. Cap |45 is preferably formed with a raised central portion |41 and together with ange |44 constitutes a fluid chamber |48 which is connected by a number of openings or passages |49 to grooves |43. A flexible conduit |50 is suitably positioned to communicate with chamber |48 and, as shown, is threadedly secured at one end to upper portion |41 of cap |45 and at the other end to a part of the magazine casting A passage |5| in said casting is adapted to connect exible conduit |50 to a second iiexible conduit |52 when the cone and magazine are operatively assembled. A suitable washer |5|a is interposed between conduit |52 and the end of a tube |5|b which forms the lower portion of passage |5I. The suction passage is broken at the washer when the magazine is removed from the cone.

Means to be hereinafter more fully described,

are provided in cone 24 fo;` controlling the uid pressure in flexible conduit |52 and, when cone and magazine are assembled, said means through passage |5| and conduit |50 are operatively connected to fluid chamber |48 and, therefore, adapted to regulate the pressure therein. By decreasing the pressure in said chamber to sub-atmospheric pressure, a suction is created in grooves |43 whereby the film, even though loosely stretched across the base of pressure plate 63 is forced into contact with said base. In this manner, the film is fixed in the plane of the :base of said pressure 'plate and when the latter is in lowered position and supported by nished surface |2I, said base plane in which the film is fixed is coincident with the'focal plane. Said pressure means also operates to fix the lm in the focal plane immediately prior to the release of the shutter mechanism. `It will be understood that the above-described results may be produced by utilizing suitable pressure means to 'create a pressure -above atmospheric in the camera cone and by opening grooves |43 to the atmospheric pressure in the magazine, thereby producing a pressure differential tending to force the film into contact with the pressure pla-te.

In order to indicate the number of exposures made upon the film, a counter (Figs. 3, 4, and 6) is provided in the magazine and is adapted to register each exposure by the movement of calibrated drum |54 past stationary index mark |55, said drum and -mark being visible through a window |56 (Fig. 6) conveniently positioned in the cover. A casing |51 surrounds drum |54 exposing only the portion visible'through window |56 and as shown is attached to wall 28 by a screw |58. A ratchet wheel |59 (Figs. 3 and 4) is integral with or suitably fixed to drum |54 and is provided with a hub member |60, the unit -being rotatablymounted on a shaft |6| fixed between casing |51 and magazine wall 28. A coil spring |62 having one end thereof vsecured to a flange |63 on hub member |60 and the other end iixed to wall 28, normally opposes rotary movement of vratchet wheel |59 and always tends to return -of lever |64 is secured to a shaft |61 which is journalled in and extends through wall 28 and which has a second lever |68 fastened thereto on the other side of said wall. Levers |64 and |68 and shaft |61 rotate as a unit and, therefore, when arm |25 moves upward, lever |68, onv the opposite side of the -fulcrum moves downward. A pawl |69, pivotally mounted on the end of lever |68 and resiliently urged by a spring |10 in the direction of ratchet wheel |59, engages said wheel when said lever is moved downward and rotates the former a predetermined number of notches, thereby rotating drum |54 a single graduation past index mark |55. When lever |68 is moved upward, moving pawl |69 therewith, a pin |1|,

lfixed to wall 28 and extending perpendicularly therefrom, is adapted to engage pawl |69 and ilzgiise the same to disengage from ratchet wheel Novel means, rendered operable by pressing cover 25 into locked position with magazine 23, are provided for holding ratchet wheel |59 against rotation by spring |62, in a direction to return indicating drum |54 to a zero reading. Said means comprise a cantilever spring |12 fixed to casing |51 and having a curved end extending downwardly in the direction of ratchet wheel |59, said end being adapted to hold said wheel, as viewed in Fig. 4, against rotation in a counterclockwise direction, when moved into engagement therewith. A member |13 slidably mounted in casing |51 is supported by spring |12 and when cover 25 is removed extends beyond the upper surface of said casing. However, when said cover is replaced, a part thereof, in the form of lug |14 (Fig, 6) ybears against and moves member |13, downward'thereby moving spring |12 into engagement with ratchet wheel |59. As a result, whenever cover is removed from magazine 23, indicating drum |54 is returned to zero position rby the action of spring |62, so that indicating drum |54 usually registers the number of exposures made from the time the cover has been positioned on the magazine.

After a film roll has been fully exposed or perhaps during exposure thereof, an occasion for removal of the magazine from the cone may arise. A novel safety latch is provided in combination with pressure plate actuating lever |4| for holding the pressure plate in lowered position against the magazine casting, thereby preventing admittance of light into the magazine. The novel latch comprises a lever 335 (Figs. 1 and 8) pivotally mounted intermediate the ends thereof to lever |4| in a substantially vertical position. Ihe upper end of lever 335 is resiliently urged, by a springr 336 fixed between said end and lever |4I, to move in a clockwise direction. The lower end of lever 335 extends through an opening 331 in the magazine base and is provided with a pair of notches or openings 338 and 339, the former being positioned above the latter, and being adapted to engage a plate 340 suitably affixed to the base of the magazine and projecting beyond opening 331. With the cone removed, pressure plate 63 is in lowered position and spring 336 urges lever 335 in a direction to have plate 340 engage notch i 339 and hold the pressure plate in the lowered position against any accidental or inadvertent raising thereof. When the cone is fixed to the magazine, a lug 34| shown in broken lines in Fig. 8 engages the lower end of lever 335 and moves said lever and the notches therein away from plate 340, and out of engagement with said plate, thereby leaving actuating lever |'4| unaffected during the cyclic operations.

It is often desirable, as, for example, when threading the film from roll to roll 3|, to have pressure plate 63 held in raised position, and for this purpose, notch 339 is provided in lever 335. After removal of the magazine, lever 335 may be manually operated and raised so that notch 339, L'

instead of notch 338, engages plate 340, thereby holding actuating lever |4| vand pressure plate 63 in raised position.

Cone

Cone 24 comprises a central casting |15 substantially square in horizontal cross-section and preferably having each side thereof similar in contour to the shape of the side shown in section in Fig. 11. A casing |16, afxed to said casting and surrounding the same, encloses the driving and control mechanisms, to be hereinafter more fully described, which are mounted on said casting. Locking means are provided for securing magazine 23 to said cone and, as shown 60 in Fig. 1, said locking means comprise a shaft 11 mounted for rotation in casting |15 and adapted to be rotated by a thumb screw |18 mounted on and secured to said shaft intermediate the bearings therefor and readily accessible from the outside of casing |16. Rotation 0f shaft 11 by thumb screw |18 causes axial movement of members |19 into which ends |80 of said shaft are threaded, said members being slidably mounted in casting |15 and constrained to axial movement by pins |8| xed therein and radially extending therefrom, into longitudinal grooves |82 in said casting. The longitudinal displacement of members |19 caused by rotation of thumb screw |18 moves said members into or out of openings |83 provided therefor in magazine 23 and locks or unlocks cone 24 into or from operative position upon said magazine. In the embodiment illustrated, a second lock, of like construction to the above, is provided in the cone, and engages the opposite side of magazine 23.

The camera is operable either by manual or motor means and is shown as having a readily accessible hand crank |84 and a motor |84a, either of which may be utilized for actuating the driving and control mechanisms of the camera. Crank |84 is mounted on a shaft |85 and directly rotates, when turned, a bevel gear |86 which is formed with or secured to said shaft (Figs. 1 and 10). Bevel gear |86 meshes with a second bevel gear |81 and thereby drives, through spur gear |88, the latter two gears being mounted on the same shaft, two gears |89 and |90, which mesh with said spur gear. Motor |84a is connected by Ispring coupling |a to gear |89, said coupling being of the type adapted to transmit a torque in only one direction, i. e., making a driving connection from the motor to the gear Only.

Insthe illustrated embodiment, motor |84a is suspended from the upper part of cone casting |15 by means such as screws |86a and comprises a casting |810. (Figs. 21 and 22) in which an armature |88a is supported by ball bearings |89a. 'Ihe usual field winding |90a is provided, and a shaft |9|a rotates with armature |88a and has a worm |920, formed integrally therewith. 'I'he latter engages and drives a gear |930, operatively connected to coupling |85a, thereby driving gear |89.

Gear |89 is integral with or suitably keyed to a shaft |9|, said shaft being mounted for rotation in downwardly extending brackets |92 and having a worm |93 and a jaw clutch plate |94 mounted thereon. Clutch plate |94 is adapted to operatively engage a corresponding plate |95 aixed to a second shaft |96 and to drive said second shaft when so engaged. Shaft |96 extends through and is journalled in brackets |91 and has a bevel gear |98 mounted thereon which meshes with a second bevel gear |99, the latter being secured to a hollow shaft 200, and thereby being adapted to drive the lower member of jaw coupling |02 which is also secured to said hollow shaft. Jaw coupling |02 has the upper and lower portions thereof operatively engaged and directly connecting shafts 200 and |03 when the cone is locked to the magazine.

As hereinbefore described, shaft |03, when driven through coupling |02, actuates the mechanisrn which meters the film and said film is metered during only a predetermined portion of the time necessary for the performance of the complete cycle of operations required to take each exposure. Accordingly, means are provided for automatically engaging and disengaging jaw clutch plates |94 and |95 at predetermined points lof the operating cycle, thus controlling the operating period of the mechanism, including shaft |03 and metering drum 64 which is driven from clutch plate |95. In order to be disengaged from 'clutch plate |95, plate |94 is slidably keyed to shaft |9| and has a collar 20| integral therewith, said collar being adapted to cooperate with a yoke 202. Yoke 202 is formed integrally with a pivotal arm or lever 203 on which a roller 4follower 204 (Fig. 10) is mounted, the latter being actuated by a cam 205 and being urged into contact with said cam by a coil spring 203a xed at one end to cone casting and at the other end to arm 203. Rotation of said cam oscillates arm 203 and thereby actuates collar and controls the engagement of clutch |90, |95.

s Cam 205 is mounted on a shaft 205 which is driven through a worm and worm wheel drive, comprising worm |93 and a worm wheel 201, from shaft 9| and, therefore, is continuously rotating during the cycle of operations. The gears are preferably designed so that cam 205 moves a single revolution during each cycle of operations and said cam is designed to keep clutch |94, |95 engaged during approximately a half of said cycle, the film being accurately metered by drum 60 during said half cycle.

For the purpose of raising pressure plate 63 once during each cycle of operations, to free the film for metering in accordance with the abovedescribed method, means are provided for actuating rod |02 (Fig. 8) which, as hereinbefore described, operates the mechanism for raising and lowering said pressure plate, A rod 208 (Fig. 1) is slidably mounted in and extends through hollow shaft 200 and, when jaw clutch |02 is drivingly engaged, said rod is adapted to move upward and have its upper end bear against the lower end of rod |02, lifting the latter rod and raising pressure plate 63 through arm |4|. The reciprocal movement is imparted to rod 208 through a cam mechanism comprising a roller cam follower 209 and a cam 2 I0, the former being pivotally xed to the .portion of said rod extending beneath bevel gear |99 and the latter being mounted on a shaft 2| which is driven through a helical gear 2 |2 mounted thereon and meshing with a second helical gear 2|3 secured to shaft 209. Shaft 2|| is thus driven from crank |84 or motor |84a and rotates continuously during the cycle of operations and preferably moves a single revolution causing cam 2|0 to raise and lower pressure plate 63 once during each cycle.

In order to produce the suction which xes the lm in the base plane of pressure plate 63, pressure means comprising a plurality of bellows are provided, said bellows being adapted to expand rapidly from a collapsed position and thus have the pressures therein materially decreased. In the illustrated embodiment, two bellows 2|5, 2|5 (Fig. 10) are shown as being supported on a member 2|0 carried on casting |15, said member having an opening 2 1 (Fig. l1) therethrough which connects each of said bellows to conduit |52 and, therefore, to chamber |48. Thus, a suction, if created in said bellows, will also exist in said chamber and in grooves |43, urging the film into contact with pressure plate 63.

Bellows 2| 5 are collapsed by suitable means against the resisting force of coil springs 2|0 located within said bellows and, when said collapsing means are released, said springs tend to return to normal position, thereby rapidly expanding the bellows. The collapsing means comprise a plate or bar 2|9 which extends over and rests upon the tops of said bellows and may be xed thereto, and a rod 220 fixed to said bar intermediate the ends thereof. Rod 220 has gear teeth formed thereon and constitutes a rack which meshes with a pinion 22| freely mounted for rotation on a shaft 222, said shaft being journalled in and extending between brackets 223 and 224 secured to cone casting |15. A lug-225 is formed integrally with bracket 223 and, has an opening therein in which rod 220 is'mounted and which guides said rod during reciprocal motion thereof; Another lug 226 provided with an opening therein is also formed integrally with bracket 223 and serves as a guide for a rod 221 fixed to plate 2 |9 and extending upwardly therefrom parallel to rod 220, said lugs and said rods keeping plate 2 9 horizontal during the collapsing and expansion of bellows 2|5.

When pinion 22| rotates in a clockwise direction, as viewed in Fig. 13, rack or rod 220 is moved downward, said downward motion being transmitted by plate 2 9 to bellows 2| 5, collapsing said bellows against the resistive force of springs 2|8.

This rotation of pinion 22| is accomplished by a pawl 228 (Fig. 12) pivotally mounted to a gear 299 and rotatable therewith, said pawl engaging notches in a hub 230 of said pinion and being held in engaged position with said notches by a plate spring 23| fixed to said gear. Plate spring 23| applies a counter-clockwise torque to pawl 22B which, when overcome, causes said pawl to pivot in a clockwise direction and release hub 239, thereby releasing pinion 22| for free rotation about shaft 222.

Gear 229 is mounted on shaft 222 and is driven by a gear 232 fixed to a shaft 233, the latter gear being adapted for continuous rotation during the operating cycle and accordingly continuously driving gear 229 in a clockwise direction. Shaft 233 is driven by a worm and worm wheel 234 from a shaft 235 which, in turn, is driven through gear |90, thereby constituting a drive from motor |34a.

For reasons hereinbefore stated, a suction is to be created on the pressure plate side of the film when said pressure plate is about to be lowered and again at the moment when the photograph is taken, thus requiring that bellows 2|5 expand twice during a single operating cycle. Accordingly, means are provided whereby pinion 22| is-automatically released from gear 229 when pressure plate 63 is about to be lowered, causing bellows 2|5, which up to that part of the cycle are being collapsed, to expand and create the desired suction. For this purpose, a bracket 236 (Fig. 12) suitably xed to casting |15 has an arm 231 extending vertically upward therefrom, said arm being adapted to engage a lug 238 which is integral with pawl 228 and to apply a clockwise torque to said pawl by engaging said lug. Application of said torque to said pawl causes the same to be released from hub 230 and thereby permits bellows 2 I5 to expand and move the film into contact with pressure plate 63. The release of said pawl from said hub is preferably timed, by suitable choice of gearing and suitable positioning of arm 231, to occur substantially at the moment when pressure plate 63 reaches the focal plane determined by surface |2I.

As gear 229 continues to rotate, pawl 228 movesY past arm' 231 and again operatively engages hub 230, thereby collapsing bellows 2 5 for a second time. When the bellows are fully collapsed, gear 229 has rotated a single revolution during the cycle and assumes a position corresponding to the initial position held thereby. In order to create a suction and simultaneously expose the film, novel means, to be described, are provided whereby the release of the bellows also controls the operation of the shutter mechanism. The shutter curtain, however, is moved for an exposure only by the second cyclic expansion of the bellows, the control mechanism being unresponsive to the rst expansion.

'Release of the bellows for the second cyclic expansion is accomplished either manually or automatically by means shown in Figs. and 1l. The manual means comprise a push button 238 slidably mounted in a supporting arm 239 of a handle 249, said arm being xed to or integral with casting |15. A coil spring 24|, interposed between push button 238 and arm 239, acts normally to project the upper portion of said button beyond the surface of said arm,` and said button has the lower end thereof adapted to actuate one end of a lever 242.. Lever 242 is fulcrumed for pivotal movement about a horiaontal axis in a groove 243 in arm 239, by means of a screw or pin 244 mounted in said arm. The other end of lever 242 extends through casing |16 into cone 24 and is adapted to engage an arm 245 of a pivotal member 246, said member being mounted for rotation about an axis perpendicular to the pivotal axis of lever 242, and being held in position on said axis by nuts 241. Member 245 consists of a fiat plate having two arms 245 and 249 integral therewith and disposed on opposite sides of the axis of rotation. Arm 249 extends parallel to said axis and engages a pin 250 slidably mounted in a support 25| fixed to bracket 224, said pin being yieldingly held against downward movement by suitable means such as a spring 252 positioned between said support and a washer 253 secured to said pin. Support 25| is so mounted relative to gear 229 (Fig. l2) that pawl 228 is directly under pin 259 when the pawl has caused bellows 2|5 to be collapsed for a second time, said pin being adapted to move said pawl clockwise when moved downward.

To disengage pawl 228 from hub 239 and expand bellows 2|5, push button 238 is depressed against the resistance of coil spring 24| to actuate lever 242, thereby raising arm 24'5 of member 246 and lowering arm 249 by overcoming the resistance of spring 252. As arm 249 and therefore pin 250 are moved downward, the latter moves pawl 228, releasing pinion pinion 22| and permitting springs 2|8 to expand bellows 2|5, thus creating a suction in the grooves |43 of pressure plate 63 and thereby causing the film to adhere to the base plane cf said pressure plate.

A solenoid 254, shown in the illustrated embodiment as positioned beneath pivotal member 246, is adapted, when energized, to attract said member and thereby operate the pawl releasing mechanism above described. The solenoid is utilized to effect an automatic control of the releasing mechanism by being connected to a source of electrical energy through a switch controlledby an interval meter.

Shutter mechanism and lens A wide angle lens comprising elements 255 (Fig. 20) is supported by members 256 which are in turn supported and accurately aligned on anges 251 and 258 provided therefor in cone casting |15, said members being secured to said anges by means such as screws 258a. It will be noted that the cone casting carries the lens members and also provides the surface for determining the plane of the lm, thus minimizing the possibility of misalignment between the lens and the nlm plane when the former is positioned during assembly.

The image of the object to be photographed is focused on the film by said lenses and impressed thereon when said film is exposedY to the light by movement of a novel shutter curtain. 2.59. Curtain 259, which is mounted in a novelv manner so as to be operative between the lenses, is adapted to be moved at various speeds to admit a predetermined amount of light through the lenses despite varying atmospheric conditions. Because cf the rapidity with which the curtain must move in order to correctly control the passage of light, sudden forces of varying magnitudes are being intermittently applied in dierent directions to said curtain. In the present invention, in order to reduce or entirely eliminate the possibilities of some form of deformation in curtain 259 due to said forces, a novel curtain is provided. The latter is preferably composed of a suitable flexible metal such as beryllium copper, although a thin, finely meshed, metal screen which is impregnated with rubber or other opaque material may ybe successfully utilized.

Novel curtain drums or rolls 269 and 26| are provided for novelly mounting and driving curtain 259, and each comprises (Figs. 14 and 19) a central shaft 262 journalled for rotation in a substantially square frame or support 263. A pair of collars 264, 264, loosely mounted on central shaft 262, are secured to a hollow cylindrical drum 265 concentric with the axis of said shaft. Drum 265, to which curtain 259 is xed and about which it is wound, is driven through a yielding drive comprising a plurality of wires 266, two being shown in the illustrated embodiment, which areV slidably fixed at the ends in collars 264 and rigidly fixed at the centers in a collar 261. The latter collar is pinned to shaft 262 and rotatable therewith when said shaft is driven through bevel gear 268 mounted thereon. As a result of the above-described structure, drum 265 is driven through said wires and is permitted a limited degree of rotation relative to shaft 262, depending upon the resiliency of wires 266 and the manner in which said wires are held in collars 254.

Both of the curtain rolls are similarly constructed and curtain 259 is suitably wound on said rolls and is adapted to be moved from one roll to the other exposing a new frame of lm each time it is moved. Since drums 265 are exactly alike in construction and dimensions, the effective diameter of one roll decreases as that of the other increases when the curtain unwinds from the former to the latter during an exposure, due to the increasing number of curtain thicknesses upon the latter. If, under these circumstances, drums 255 are driven at the same angular velocity, a difference in linear velocities would arise at the drum peripheries tending to wind the curtain at a more rapid rate than it is being unwound and therefore causing an excessive tension or elongation to be produced in said curtain. Accordingly, the yielding drives are provided for the drums whereby, although the central shafts are driven at equal speeds, the drums are permitted relative rotation thereto, sufficient to compensate for the increasing and decreasing diameters resulting from differences in the number of curtain layers wound on the drums. As a further result of the novel drive construction, it is possible to constantly keep curtain 259 taut since'said curtain may readily be mounted on drums 265 under an initial tension. Furthermore, the initial sudden load imparted to the shaft when an exposure is to be made is absorbed in part by the resiliency of the drive, causing a more uniform application of the force to the curtain.V

It is highly desirable that the lens elements, once accurately fixed in position, remain undisturbed thereafter, and therefore frame 263 is suitably constructed and curtain 259 and rolls 260 and 26| are suitably mounted thereon, to

have the shutter mechanism adapted for ready removal from operative position as a unit without aifecting the lens. As shown, frame 263 comprises a U-shaped casting having the two parallel arms 269 and 21'9- thereof supporting rolls 269 and 26|, respectively, and said arms and rolls are fitted into operative position by inserting frame 263 into cone casting with the open end of the U-shaped casting foremost. Curtain 259 fits between the lenses and a thin plate 21| may be secured across the open end of said casting in the horizontal plane of said curtain, thus adding to the rigidity of the structure and not detracting from its removability, since said plate, when frame 263 is inserted or removed, passes freely between the lens elements along with curtain 259.

Curtain rolls 269 and 26| are adapted to be driven by means which automatically alternate the direction in which said drums are rotated after each exposure causing the curtain to be alternately wound and unwound from each roll and to expose a film frame each time it is moved across the lenses. As illustrated in Figs. 14 and 16, said curtain rolls are driven through bevel gears 268 mounted on central shafts 262 of said rolls and said gears mesh with a pair of bevel gears 212 secured to a shaft 213. Shaft 213 is in turn adapted to be driven through either of two gears 214, 214 loosely journalled thereon and driven in opposite directions by an annular gear 215. A sleeve 216 slidab-ly keyed between gears 214 to shaft 213 for rotation with said shaft has a collar 211 integral therewith and is provided with axially extending lugs or pawls 218 on each end thereof. The hubs of gears 214 extend beyond the faces of said gears in the direction of sleeve 216 and have suitable openings 219 therein adapted to be engaged by lugs 218. When sleeve 216 is moved in the direction of one of gears 214, that gear is engaged by those of lugs 218 on the adjacent end of said sleeve and a driving connection in the nature of a jaw coupling from annular gear 215 to curtain rolls 269 and 26| is established.

When an exposure is taken, gear 215 is driven at a predetermined high velocity, by means to be described, and moves curtain 259 and the opening therein past the lenses by means of the connection above described. If this movement of the curtain is, for example, to the right, as viewed in Fig. 14, then said curtain is wound upon drum 26| and for the next exposure must be unwound therefrom and moved in the opposite direction. Accordingly, during the interval between exposures while the new frame of lm is prepared for exposure, sleeve 216 is automatically moved into engagement with the other of gears 214 thereby reversing the drive to the curtain rolls so that when gear 215 is next driven for an exposure, the curtain moves to the left, i. e., from the roll 26| to roll 269.

The means for moving sleeve 216 and thereby reversing the curtain roll drive are best shown in Fig. 16 and comprise a yoke 289 which cooperates with collar 211, said yoke being integral with a plate or arm 29|. The latter is, in turn,.secured to or formed with a shaft 282 slidably mounted for reciprocal movement in supports or brackets 293 which are an integral part of frame 263. A member 284 mounted on and suitably pinned to shaft 282 between supports 293 is provided with a groove 235 in the base thereof which extends in a direction perpendicular to the axis of said shaft. A pin 296 eccentrically mounted on or formed with rotary disc or plate 281 cooperates with said groove and is adapted to translate the rotary motion of said disc into reciprocal movement of member 284, thereby actuating sleeve 216. It will be understood that any other suitable linkage, such as a crank and connecting rod, could be employed to impart reciprocal movement to member 284 or to sleeve 216 directly. In the illustrated embodiment of the invention, disc 281 preferably rotates a half revolution during each operating cycle, moving sleeve 216 from one extreme position to the other during the single cycle, i. e., out of engagement with one of gears 214 and into engagement with the other. Disc 281 is preferably integral wtih a shaft 288 driven by a bevel gear 299 which meshes with a second bevel gear 299. The latter gear is secured to shaft 296 (Figs. 1 and 14) which also drives the cams that control the pressure plate and the vmetering roll mechanisms.

A high turning torque must necessarily be applied to gear 215 in order that said gear may rotate at a sufficient angular velocity to produce desired exposure speeds of curtain 259. To im- ,part such a torque to said gear, a` spring drive vthe other end to said shaft and is adapted to drive the latter, thereby driving gear 215. Means, to be described, are provided whereby shaft 293 is held against rotation during the operating cycle while drum 29| rotates relative thereto in a direction to wind spring 292. A torque tending to turn said shaft is thus set up in the spring, the magnitude of the torque depending on the amount of relative rotation between drum 29| and said shaft. When shaft 293 is iinally released for rotation, it is driven by said spring and moves curtain 259 to expose the film for a photograph.

Drum 29| is rotated to wind spring 292 by being threadedly secured to a hub 294 of a bevel gear 295, the latter being part of a differential drive. The drive comprises a pair of bevel gears 296 and 291 mounted for Arotation on shafts 298 and 299, respectively, said shafts being journalled in a worm gear 399. Worm gear 399 has suitable openings therein for receiving gears 296 and 291, and is freely mounted upon a shaft 39| rotating about an axis that is perpendicular to the axis of shafts 293 and 299. A bevel gear 392, shown integral with shaft 39|, meshes with gears 296 and 291 and is adapted to drive gear 295 when gear 399 is fixed against rotation and when shaft 39| is driven by a gear 393 pinned to said shaft. Gear 393 is operatively engaged by a bevel gear 394, shown in Fig. 1, the latter being mounted on a shaft 395, and said shaft is adapted to be driven by a worm and worm wheel drive 396 from shaft |96 (Fig. 10). Accordingly, drum 29| is driven for the same interval that the main film is being metered, and the spring drive is wound by said rotation, being prepared for moving curtain 259.

Novel means operable in conjunction with bellows 2|5 are provided whereby shaft 293 is held Y against release while drum 29| Winds spring 292 and whereby said shaft and, therefore, shutter curtain 259. are released for movement, with the second cyclic expansion of said bellows. The means comprise a pair of cams or ratchet wheels 391 and ,398 of similar peripheral contour each being provided with a single notch, and both being suitably mounted on shaft 293 so as to be displaced 180 to each other. In the illustrated embodiment, cani 391 is shown integral with shaft 293 and cam 338 is secured to the former by suitable means, such as rivets 399. During the major portion f the cycle of operations, shaft 293 is held against release, i. e., against clockwise rotation as viewed in Fig. 17, by a lever 3|9 pivotally mounted about a pin 3| An arm 3| 2 of said lever is adapted to engage the notch in cam 39S, thereby holding the same against rotation in a clockwise direction. A second arm 3|3 also formed with said lever bears against the periphery of a cam 3M mounted on shaft 288, and is yieldinglyheld in contact with said cam by a coil spring 3|5. Coil spring 3 5 is fixed at one end to arm 3l3 and at the other end to a supporting plate 3|5 in which pivot pin 3|| is mounted and which is secured by means such as screws 3|1 to frame 263. Cam 3|4, as shown, comprises a circular disc having two symmetric and radially projecting portions 3|8 and 3|9 integral therewith and disposed diametrically opposite each other and adapted to pivot lever 3|!) in a clockwise direction when brought into contact with arm 3 |3. Shaft 288 which actuates the means for reversing the shutter drive rotates a half revolution every cycle of operations and cam 3M is suitably positioned on shaft 288 to have lever 319 pivoted thereby substantially at the end of the cycle.

When lever 3|0 is pivoted in a clockwise direction, as viewed in Fig. 17, arm 3|2 moves away from cam 308 and becomes disengaged from the notch therein, thereby permitting rotation of said cam and of shaft 293. At this point in the cycle of operation, the bellows 215 have been collapsed a second time and a pin 320, actuated by said bellows in a manner to be hereinafter described, is in position to engage the notch in cam 381. This limits the rotation 0f shaft 293 to a displacement that is only sufficient to move the notch in cam 398 past arm 3|2 and to free shaft 293 from said arm. Shaft 293 is then held against rotation by pinV 329 and when said pin is disengaged from the notch in cam 3D1, shaft 293 is rotated substantially a single revolution and curtain 259 is moved thereby to expose the film. The total rotary movement of shaft 293 during each cycle of operation willnot exceed a single revolution, since cam 398 is held by lever 3|2 at the start of the operation and at the completion of the cycle after an exposure has been taken, i. e., after pin 329 has been disengaged from cam 331, said lever again engages and'holds said cam.

In order that the release of shutter curtain 259 be concurrent with the second expansion of the bellows, pin 329` is suitably secured to or formed integrally with a rod 32|, said rod being slidably mounted for reciprocal movement in a bracket or bearing member 322 which is a part of supporting member 3|8. A bushing 323 is fixed in member 322 and a collar 324 is attached to rod 32|, so that a compressed coil spring 325 interposed betweensaid bushing and said collar tends to keep pin 32|! in engagement with cam 301. A portion of rod 32| extends rearwardly in a horizontal plane substantially at right angles to the axis of the part slidabl'e in bracket 322 and serves as a cam follower, engaging a cam 326 fixed to plate 2|9 of the bellows structure. Cam 326 has an edge 321 thereof adapted to cooperate with rod 32| in such a manner that when the bellows are in collapsed position, pin 320 is in engagement with cam 301 as shown in full lines in Fig. 17.

However, when the bellows are expanded', said cam takes a position, shown by broken lines in Fig. 17, having been moved upward and having caused rod 32| and pin 320 to move to the right and away from cam 301 to clear the notch therein. Bellows 2 5, for reasons hereinbefore disclosed, are expanded twice during the operating cycle, and both times pin 320 is moved to the right and away from cam 391. Nevertheless, the first expansion does not release the shutter mechanism as shaft 293 is then held against rotation by arm 3|2 of lever 3|9 which is in engagement with the notch in cam 398. However, just prior to the completion of the second collapse of the bellows, cam 3| 4 pivots lever 3H] and permits shaft 293 to rotate the limited amount necessary to keep arm 3|2 disengaged from the notch in cam 308 for a complete revolution so that shaft 293 is then held against rotation only by pin 320. Accordingly, when the bellows are expanded for a second time, shaft 293 is freed for substantially a complete revolution and moves shutter curtain 259 for an exposure. Thus, the shutter mechanism can be actuated to expose the film only after the cycle of operations, metering and positioning the lm, is completed. In order to control the operation of motor |8411, lever 3H) has a horizontally extending arm 3||la (Fig. 17) adapted to actuate a switch 3Illb. The latter, which is suitably mounted on cone casting |15, is connected in the circuit of motor |84a and breaks said circuit when said lever is rotated clockwise as by projection 3|8 cr 3|9 of cam 3| d. After the motor circuit is thus broken, the inertia of the moving parts continues the rotation of said cam until the projecting portion causing the break moves past arm 3|3. However, the motor circuit is not closed again by this additional rotation but instead remains open, lever 3||l being held in the displaced position by cam 398 until the shutter is released. Accordingly, the motor will not resume operation until a new frame of film must be prepared for exposure.

Means are provided whereby the speed of curtain 259 and therefore the exposure timing may be selectively controlled, said means comprising a knob 328 or other manual control (Figs. 1 and 14) readily accessible from the exterior of casing |13. Knob 328 is operatively connected to a bevel gear 329 through which said knob is adapted to drive a second bevel gear 338 mounted on a shaft 33|. A worm 332 affixed to or integral with said shaft meshes with gear 300, thereby completing a drive from knob 328 to drum 29|, since rotation of gear 399 is transmitted to said drum through gears 296 and 291 and gear 295. The speed of gear 215 and therefore the speed of curtain 259 depends on the torque applied thereto by spring 292 which in turn is a function of the rotation of drum 29| relative to shaft 293, i. e., of the tension induced in said spring by rotation of drum 29| while shaft 293 is held against rotation. Knob 328 is adapted to vary the effective torque applied to shaft 293 by increasing or decreasing the initial tension in spring 292. Since the driving means, crank |94 or motor |84a, causes drum 29| to rotate a single revolution, and since shaft 293 upon release rotates a single revolution, the initial tension in spring 292 becomes the controlling factor in determining the speed at which curtain 259 is moved. Accordingly, knob 328 may be rotated to produce the desired curtain speed and is provided with a dial 333 suitably geared to respond to rotation of said knob and calibrated to indicate the 

